KR20070008143A - Over current detection apparatus of dual motor for car - Google Patents

Abstract

An apparatus for detecting an over current of a dual motor in a vehicle is provided to prevent the motors from being burned out by accurately detecting an over current state of the motors. An input unit(11) inputs an external square wave signal. A microprocessor provides a drive control signal to drive an FET(Field Effect Transistor) based on the motor drive information from the input unit, and stops operations of first and second motors(16,16') if necessary. A first FET driver(13) amplifies and outputs an FET drive signal to drive the first motor. A second FET driver(13') is connected to one end of the first FET driver for amplifying and outputting an FET drive signal to drive the second motor. First and second FETs(14,14') are turned ON/OFF in accordance with each of the FET drive signals from the first and second FET drivers. First and second freewheeling diodes(15,15') passes recovery currents for continuous operation of the first and second motors. First and second shunt resistors(17,17') are connected to one ends of the first and second FETs for detecting a current of each of the first and second motors flowing in each of the first and second FETs. First and second amplifiers(18,18') detect and amplify voltages produced by the currents flowing via the first and second shunt resistors. First and second smoothing units smooth each of the voltages amplified by the first and second amplifiers.

Description

OVER CURRENT DETECTION APPARATUS OF DUAL MOTOR FOR CAR}

1 is a circuit block diagram of an overcurrent detection apparatus of a conventional dual motor for a vehicle.

2A and 2B are diagrams showing output waveforms in a normal state and an overcurrent state of a dual motor according to a conventional overcurrent detecting device.

Figure 3 is a circuit block diagram of an overcurrent detection device for a dual motor for a vehicle according to an embodiment of the present invention.

4A and 4B are views showing corresponding output waveforms in a steady state and an overcurrent state of the motor 1 according to the overcurrent detecting apparatus of the present invention.

5A and 5B are views showing corresponding output waveforms in a steady state and an overcurrent state of the motor 2 according to the overcurrent detection apparatus of the present invention.

Figure 6 is a circuit block diagram of an overcurrent detection device for a dual motor for a vehicle according to another embodiment of the present invention.

Figure 7A is a view showing each waveform of the steady current, the restraint current, the overcurrent detection reference current of the motor 1 to set the overcurrent detection reference current in the microprocessor in the overcurrent detection device according to the present invention.

Figure 7B is a view showing each waveform of the steady current, the restraint current, the overcurrent detection reference current of the motor 2 to set the overcurrent detection reference current in the microprocessor in the overcurrent detection device according to the present invention.

8 is a flowchart illustrating an overcurrent detection reference current setting operation and an overcurrent detection operation of a dual motor performed by a microprocessor in the overcurrent detection apparatus according to the present invention.

<Description of the symbols for the main parts of the drawings>

11 input unit 12 microprocessor

13,13 ', 13 ": FET driver 1,2 14,14': FET1,2

15,15 ': Freewheeling diode 1,2,16,16': Motor 1,2

17,17 ': Shunt resistor 1,2, 18,18': Amplifier 1,2

Amp1, Amp2: Differential amplifier 1,2 19,19 ': Smoothing part 1,2

The present invention relates to an overcurrent detection device for a dual motor for a vehicle, and in particular, in detecting an overcurrent state of a DC dual motor for a vehicle, a constant between a steady current and a restraint current of each motor for each driving input condition according to each used motor. Set the range to each overcurrent detection reference current, detect the current of each motor flowing through the FET through a shunt resistor and a differential amplification circuit, and compare with the set overcurrent detection reference current to drive the entire drive area of the dual motor. The present invention relates to an overcurrent detection device of a dual motor for a vehicle that can more accurately detect an overcurrent state of two motors as well as one motor, thereby preventing each motor from being burned out.

In general, the dual motor that provides the driving force necessary for the operation of the vehicle changes the rotational force as controlled by the microprocessor to provide the vehicle with the necessary power, which causes the overcurrent to flow due to internal, external, or restraint effects during driving. In this case, the dual motor is damaged by this overcurrent.

As such, in the related art, if the overcurrent of the dual motor is accurately detected and the driving of the dual motor is stopped to protect the dual motor, the dual motor is damaged by the overcurrent. Thus, the dual motor is prevented through the overcurrent detection apparatus shown in FIG. The overcurrent of the motor was detected.

1 is a circuit block diagram of a conventional over-current detection device for a dual motor for a vehicle, including an input unit 1 for inputting an external signal including motor driving information (duty), and an outside of the input unit 1. Outputs the FET drive control signal for driving the FET according to the motor drive information in the signal, and determines the overcurrent state of the dual motor according to the output of the comparator 9 to be described later, and stops the drive of the dual motor in the overcurrent state. Microprocessor (2) for controlling the power supply, the FET driver (3) for outputting the FET drive signal in accordance with the FET drive control signal of the microprocessor (2), and the FET drive signal of the FET driver (3). Transistor FET 4, which is a dual motor driving element for simultaneously driving dual motors by off operation, and a freewheeling diode 5 for passing a regenerative current for continuous operation of the dual motors when the FET 4 is off. In addition, the motor 1 (6) and the motor 2 (6 ') which is driven in accordance with the operation of the FET 4 and the freewheeling diode 5 to provide the driving force required for the vehicle operation, and the FET 4 The voltage detection unit 7 which detects the detection voltage which is the voltage across the FET 4 generated by the current flowing through the internal resistance, and the overcurrent detection voltage according to the motor 1 (6) and the motor 2 (6 ') are referred to as reference voltages. When the detected voltage is smaller than the reference voltage by comparing the reference voltage setting unit 8 and the detected voltage of the voltage detector 7 with the reference voltage of the reference voltage setting unit 8, the normal state is high. The output voltage is large, and the comparator 9 outputs a low output voltage in an overcurrent state to the microprocessor 2, respectively.

2A and 2B are diagrams showing output waveforms in a normal state and an overcurrent state of a dual motor according to a conventional overcurrent detecting apparatus. Referring to this, the operation of the conventional overcurrent detecting apparatus will be described below.

The microprocessor 2 in the conventional overcurrent detecting device receives motor driving information included in an external signal from the input unit 1, and controls the FET driving unit 3 according to the motor driving information to control the FET 4 as a dual motor driving element. ). When the FET 4 is turned on, the power is applied to the motor 1 6 and the motor 2 6 'while the power is applied. When the FET 4 is turned off, the motor 1 6 and the motor 2 ( The regenerative current generated at 6 ') flows through the freewheeling diode 5 to drive the dual motor 1 and the second motor 6' continuously.

At this time, the FET 4 has an internal resistance, and the on operation of the FET 4 changes according to the motor driving information, and both ends of the internal resistance of the FET 4 according to the current change due to the on operation of the FET 4. The voltage generated during the change will change.

Thereafter, the comparator in the comparator 9 compares the detected voltage of the voltage detector 7, which has detected the voltage across the FET 4, with the reference voltage of the reference voltage setting unit 8, and if the detected voltage is less than the reference voltage. If the output voltage of 5V is large, the output voltage of 0V is output to the microprocessor 2, respectively.

Then, the microprocessor 2 checks the output voltage of the comparator 9 and determines that the motor 1 6 and the motor 2 6 'are in a normal state when the output voltage is 5V. In the case of a voltage, it is determined that an overcurrent flows through the motor 1 (6) and / or the motor 2 (6 '), and the driving of the motor 1 (6) and the motor 2 (6') is stopped so that the motor 1 (6) and / or The motor 2 6 'is prevented from being burned out by overcurrent.

However, in the overcurrent detection apparatus of the conventional dual motor for a vehicle as described above has the following problems.

That is, the internal resistance of the FET is slightly different every time the FET is manufactured, and even in the same FET, since the internal resistance of the FET changes with temperature, the distribution of the detection voltage generated by the current flowing through the FET increases. .

Therefore, even when compared with the reference voltage, the detection voltage exceeds the reference voltage even in a normal state, the dual motor is stopped, thereby providing a problem that can not provide the power required for the vehicle operation. In particular, in the case of an engine cooling motor, the engine is overheated and the vehicle is prevented from moving.

In addition, despite the overcurrent condition, if the detection voltage is lower than the reference voltage and the dual motor is continuously driven and a large current flows, the dual motor may be burned out.

In addition, the reference voltage for detecting the overcurrent set by the reference voltage setting unit cannot be changed, so even when a motor overcurrent phenomenon occurs under a low current motor driving condition, the detection voltage becomes less than the reference voltage and thus cannot detect the overcurrent state of the dual motor. There was a problem that the dual motor burned out.

In particular, when dual motors are driven simultaneously, when one motor of small capacity is constrained, it is summed with the current of another motor of large capacity, so that the overcurrent condition of the small motor can be detected in the range lower than the normal maximum current of the large motor. No, a small motor eventually burns out.

The present invention is to solve the above problems, the purpose of which is to detect the over-current state of the automotive DC dual motor, the constant between the steady current and the restraint current of each motor for each drive input condition according to each use motor Set the range to each overcurrent detection reference current, detect the current of each motor flowing through the FET through the shunt resistor and the differential amplifier circuit, and compare it with the set overcurrent detection reference current to determine the The present invention is to provide an overcurrent detection device of a dual motor for an automobile that can more accurately detect an overcurrent state of two motors as well as prevent each burnout from occurring.

An overcurrent detection apparatus for an automotive dual motor of the present invention for achieving the above object includes an input unit configured to input an external square wave signal including motor driving information (duty) to a potential recognizable by a microprocessor to be described later. And outputting a FET driving control signal for driving the FET according to the motor driving information in the external square wave signal of the input unit, and the normal current of each motor for each driving input condition according to each using motor in the entire driving region of the dual motor. A certain range between the restraint currents is set to the respective overcurrent detection reference currents 1 and 2 for determining the overcurrent state, and the motor detection currents 1 and 2 corresponding to the output voltages of the smoothing parts 1 and 2 to be described later and the set reference currents. Comparing 1,2, respectively, if the detected current 1 is smaller than the reference current 1, it is determined that the motor 1 is in a normal state, and if it is large, it is determined as an overcurrent state. If the detected current 2 is less than the reference current 2, it is determined that the motor 2 is in a normal state. If the detected current 2 is larger, it is determined as an overcurrent state. If one of the two motors is determined to be in the over current state, the motor 1 and 2 are stopped. A microprocessor, a FET driver 1 for amplifying and outputting a FET drive signal for driving the motor 1 according to the FET drive control signal of the microprocessor, and a micrometer connected to one end of the FET driver 1 and output to the FET driver 1 A FET driver 2 for amplifying and outputting a FET drive signal for driving the motor 2 according to a FET drive control signal of a processor, and FETs 1 and 2 operating on / off according to each FET drive signal of the FET drivers 1 and 2; When the FETs 1 and 2 are off, the freewheeling diodes 1 and 2 passing through the regenerative current for the continuous operation of the respective motors 1 and 2, and the FETs 1 and 2 and the freewheeling diodes 1 and 2 Motors 1 and 2 which are driven in accordance with the present invention and provide driving force required for vehicle operation, shunt resistors 1 and 2 connected to one ends of the FETs 1 and 2 and detecting currents of the motors 1 and 2 flowing through the respective FETs 1 and 2; Amplifier for detecting and amplifying the voltage generated by the current flowing through each of the shunt resistors 1 and 2 while eliminating the effect of the ground potential that changes according to the current for each motor capacity generated when driving a dual motor using a differential amplifier. 2 and a smoothing unit 1 and 2 for smoothing each of the voltages amplified by the amplifying units 1 and 2 and outputting the smoothed voltage to the microprocessor.

Hereinafter, with reference to the accompanying drawings will be described in detail the configuration and operation of the overcurrent detection device of a dual motor for a vehicle according to the present invention.

3 is a circuit block diagram of an overcurrent detection apparatus for an automotive dual motor according to an exemplary embodiment of the present invention, in which an external square wave signal including motor driving information (duty) may be recognized by the microprocessor 12 to be described later. An input section 11 inputted by changing to a 5V potential and a FET drive control signal for driving the FET according to the motor drive information in the external square wave signal of the input section 11; Set a certain range between the normal current and the restraint current of each motor for each driving input condition according to the used motor to the respective overcurrent detection reference currents 1 and 2 for determining the overcurrent state, and the smoothing unit 1, 2 (19, Motor's detection currents 1 and 2 corresponding to the output voltage of 19 ') and the set reference currents 1 and 2 are compared, respectively, and if the detection current 1 is less than the reference current 1, it is determined that the motor 1 is in a normal state. If the detection current 2 is less than the reference current 2, it is judged as an overcurrent state. If the detection current 2 is smaller than the reference current 2, it is judged as a normal state for the motor 2, and if it is large, it is determined as an overcurrent state. A microprocessor 12 for controlling to stop the driving of 2, an FET driver 1 13 for amplifying and outputting a FET drive signal for driving the motor 1 according to the FET drive control signal of the microprocessor 12; FET1 (14) on / off operating in response to the FET driving signal of the FET driver (1) 13, and a freewheeling diode through which a regenerative current for continuous operation of the motor 1 is passed when the FET1 (14) is off. 1 (15), the motor 1 (16) which is driven by the operation of the FET 1 (14) and the freewheeling diode 1 (15) to provide the driving force required for the vehicle operation, and is connected to one end of the FET 1 (14) Of motor 1 (16) flowing through FET1 (14) The shunt resistor 1 (17) for detecting the current and the differential amplifier (Amp1) through the shunt resistor 1 (17) while eliminating the ground potential effect that changes according to the current for each motor capacity generated when driving the dual motor An amplifying unit 1 (18) for detecting and amplifying a voltage generated by the flowing current, a smoothing unit (19) for smoothing the voltage amplified by the amplifying unit (1) 18 and outputting it to the microprocessor (12); The FET driver 2 which is connected to one end of the FET driver 1 13 and amplifies and outputs the FET drive signal for driving the motor 2 according to the FET drive control signal of the microprocessor 12 output to the FET driver 1 13. 13 ', FET2 14' that is turned on / off according to the FET drive signal of the FET driver 2 13 ', and when the FET2 14' is turned off for continuous operation of the motor 2. Freewheeling diode 2 (15 ') through which a regenerative current passes, and freewheeling with FET2 (14') Motor 2 16 'which is driven according to the operation of diode 2 15' and provides driving force necessary for the vehicle operation, and motor 2 16 which is connected to one end of FET2 14 'and flows to FET2 14'. The shunt resistor 2 (17 ') for detecting the current of') and the differential amplifier (Amp2) and the ground potential effect that changes according to the current of the motor capacity generated when driving the dual motor while removing the shunt resistor 2 ( Amplifying section 2 (18 ') for detecting and amplifying a voltage generated by the current flowing through the current flowing through the 17'), and amplifying the voltage amplified by the amplifying section 2 (18 ') to output to the microprocessor (12). It consists of the smooth part 2 (19 ').

The overcurrent detection apparatus of a dual motor for a vehicle according to the exemplary embodiment of the present invention configured as described above includes the motor 1 (16), which is connected to one end of the FET driver 1 (13), with the FET driver 2 (13 ') being a dual motor. When the motor 2 (16 ') is driven at the same time, an overcurrent condition is detected for each motor. If the overcurrent condition is detected for one or two motors, the driving of both motors is stopped and the corresponding motor is stopped. This is to prevent burnout of the motor.

Dual amplifiers Amp1 and Amp2 are used to detect voltages generated by currents flowing through the shunt resistors 1 and 2 (17 and 17 ') in the amplifiers 1 and 2 (18 and 18'), respectively. When the motor is driven, it removes the influence on the current detection of the other motor by the current flowing in one motor, that is, it eliminates the influence on the current detection of the small motor when the current flows in the motor with large capacity. The current flowing through the FETs 1 and 2 (14 and 14 ') driving 2 (16 and 16') can be detected more accurately.

An operation of the overcurrent detection device for a dual motor for a vehicle according to the present invention configured as described above will be described with reference to the accompanying drawings.

4A and 4B are diagrams showing output waveforms in the normal state and the overcurrent state of the motor 1 according to the overcurrent detecting apparatus of the present invention, and FIGS. 5A and 5B are the normal states of the motor 2 according to the overcurrent detecting apparatus of the present invention. And a diagram showing a corresponding output waveform in an overcurrent state, which will be described with reference to the following.

First, in the drive control and overcurrent detection operation of the motor 1 (16) of the dual motor, the input unit 11 receives this external square wave signal when the external square wave signal SIGNAL including the motor drive information (duty) is input. The microprocessor 12 changes the voltage to a recognizable 5V potential and outputs the result to the microprocessor 12.

Then, the microprocessor 12 calculates the motor driving information by measuring the time of the high or low signal of the external square wave signal input from the input unit 11.

Subsequently, the FET driving control signal is output to the FET driving unit 1 13 to drive the motor 1 16 at the 20 KHz frequency according to the motor driving information (duty) calculated as described above.

Accordingly, the FET driver 1 13 amplifies and outputs the FET drive signal corresponding to the FET drive control signal to the FET1 14 to drive the FET1 14.

In the on operation of the FET1 14, the motor 1 16 is driven while power is applied. In the off operation of the FET 1 14, the regenerative current generated from the motor 1 16 is freewheeling diode 1 15. Motor 1 (16) is continuously driven through the flow.

At this time, when the FET1 14 that supplies the power required to drive the motor 1 16 is turned on, the shunt resistor 1 17 connected with the current flowing through the motor 1 16 under the FET 1 14 and the FET 1 14. Will flow through.

Therefore, the amplifier 1 18 detects and amplifies the voltage generated by the current flowing through the shunt resistor 1 17 while removing the influence of the ground potential that changes according to the current for each motor capacity through the differential amplifier Amp1. To the smoothing unit 1 (19).

Subsequently, the smoothing unit 1 19 smoothes the voltage amplified by the amplifying unit 1 18 and outputs the smoothed voltage to the microprocessor 12.

On the other hand, the drive control and the overcurrent detection operation for the motor 2 (16 '), the microprocessor that the FET driver 2 (13') connected to one end of the FET driver 1 (13) is output to the FET driver 1 (13) The FET driving control signal of (12) is input from the FET driving unit 1 (13), and thus the FET driving signal for driving the motor 2 (16 ') is amplified and output to the FET2 (14') and the FET2 (14 '). Drive.

In the same manner as the driving control and overcurrent detection operation for the motor 1 16, the FET 2 14 ′ is driven while the power is applied to the motor 2 16 ′, and the FET 2 14 ′ is driven. In the off operation, the regenerative current generated in the motor 2 16 'flows through the freewheeling diode 2 15' to drive the motor 2 16 'continuously.

At this time, when the FET2 14 'that supplies the power required to drive the motor 2 16' is turned on, a shunt connected to the current flowing through the motor 2 16 'is connected to the FET2 14' and the FET2 14 '. It flows through resistor 2 (17 ').

Accordingly, the amplifier 2 18 'detects the voltage generated by the current flowing through the shunt resistor 2 17' while eliminating the effect of ground potential that varies with the current of each motor capacity through the differential amplifier Amp2. And amplified and output to the smoothing unit 2 (19 ').

Next, the smoothing unit 2 19 ′ smoothes the voltage amplified by the amplifying unit 2 18 ′ and outputs the same to the microprocessor 12.

Thereafter, the microprocessor 12 inputs the analog voltage output from the smoothing unit 1 19 to convert the analog voltage into digital data corresponding to the motor detection current 1, and then converts the converted digital data, that is, the shunt resistor 1 17. And the detection current 1 of the motor 1 16 detected by the amplifying unit 1 18 and the preset overcurrent detection reference current 1, and as shown in FIG. 4A, the detection current 1 (VSen voltage) becomes the reference current 1 ( Less than Vref voltage), the motor 1 16 is determined to be in a normal state, and as shown in FIG. 4B, if the detected current 1 (VSen voltage) is greater than the reference current 1 (Vref voltage), Judging by the overcurrent state.

In addition, the microprocessor 12 inputs the analog voltage output from the smoothing unit 2 19 ′ and converts the analog voltage into digital data corresponding to the motor detection current 2, and then converts the converted digital data, that is, the shunt resistor 2 ( 17 ') and the detection current 2 of the motor 2 16' detected by the amplifying unit 2 18 'and the preset overcurrent detection reference current 2 are compared to detect current 2 (VSen voltage) as shown in FIG. 5A. If it is smaller than the reference current 2 (Vref), it is determined as the normal state for the motor 2 (16 '). If the detection current 2 (VSen voltage) is larger than the reference current 2 (Vref) as shown in FIG. ') For the overcurrent state.

As described above, the microprocessor 12 judges the overcurrent state of the motor 1 16 and the motor 2 16 'separately for the dual motor, respectively, so that any one of the two motors is constrained to determine the overcurrent state. In this case, the dual motor driving signal is turned off to stop the driving of both motors, thereby preventing the constrained motor from being burned out by overcurrent.

Meanwhile, FIG. 6 is a circuit block diagram of an overcurrent detection apparatus for an automotive dual motor according to another exemplary embodiment of the present disclosure. As shown in FIG. 6, the dual motor for automobiles according to the exemplary embodiment of the present invention illustrated in FIG. 3 is illustrated. It is almost the same as the circuit block configuration of the overcurrent detection device. Therefore, detailed description thereof will be omitted. However, as shown in FIG. 3, the FET driver 2 13 ″ is not connected to one end of the FET driver 1 13 and is configured to receive a FET drive control signal directly from the microprocessor 12.

That is, the over-current detection device of the dual motor for a vehicle according to another embodiment of the present invention configured as described above is used to separate the FET driving control signals from the microprocessor 12 to the FET driver 1 13 and the FET driver 2 13 ″. As output is possible, it detects the overcurrent condition of each motor when dual motor is driven, and as a result, if the overcurrent condition occurs in one motor, if the other motor is in a normal state, the other motor in the normal state needs to be minimized. Make sure to provide power.

On the other hand, the microprocessor 12 calculates the steady current and the restraint current of each motor for each drive input condition according to each used motor in the entire driving region of the dual motor, and each overcurrent from the calculated steady current and restraint current. The process of setting the detection reference current and the process of detecting the state of the dual motor will be described with reference to FIGS. 7A, 7B, and 8.

That is, FIG. 7A shows waveforms of steady current, restraint current, and overcurrent detection reference current 1 of the motor 1 when the motor driving input duty is 55% to set the overcurrent detection reference current 1 in the microprocessor 12. FIG. 7B shows waveforms of steady current, restraint current, and overcurrent detection reference current 2 of the motor 2 when the motor driving input duty is 55% to set the overcurrent detection reference current 2 in the microprocessor 12. 8 is a flowchart illustrating an overcurrent detection reference current 1,2 setting operation and an overcurrent detection operation of the motors 1 and 2 performed by the microprocessor 12.

First, the microprocessor 12 receives an external square wave signal including the motor driving information from the input unit 11, calculates the motor driving information from the external square wave signal (S1), and FETs according to the calculated motor driving information. Motor drive signals for driving the motors 1, 2 (16, 16 ') by driving the driving units 1, 2 (13, 13') and FETs 1, 2 (14, 14 '), that is, FET drive control signals and FET drive signals. Outputs (S2).

Next, the voltage and the ambient temperature applied to the motors 1 and 2 (16 and 16 ') are measured (S3). That is, since the motor current varies depending on the voltage and temperature applied to the motor, the amount of change according to the dual motor applied voltage and temperature is added and corrected during the calculation of the steady current and the restraint current of the dual motor, thereby allowing the dual motor to be driven according to the dual motor driving input conditions. By calculating the steady current and the restraint current flowing in the dual motor, the current flowing through the dual motor can be accurately known, and the overcurrent state can be accurately detected even when comparing the detected current with the overcurrent detection reference current.

Subsequently, the microprocessor 12 receives the motors 1, 2 (16, 16 ') and the FETs 1, 2 (14) through the amplifiers 1, 2 (18, 18') and the smoothers 1, 2 (19, 19 '). 14 ') detects the detected currents 1 and 2 of the motors 1 and 2 (16 and 16') by converting the voltage generated at the shunt resistors 1 and 2 (17 and 17 ') into input and digital data. (S4).

Then, the steady current of the motor 1, 2 (16, 16 ') corresponding to the dual motor drive input condition is calculated, and the amount of change according to the dual motor applied voltage and temperature measured in the step S3 is added and corrected. The steady current of the motors 1 and 2 (16 and 16 ') is calculated (S5).

In addition, the restraint current of the motors 1 and 2 (16.16 ') corresponding to the dual motor driving input condition is calculated, and the change amount according to the dual motor applied voltage and temperature measured in the step S3 is added and corrected to the motors 1 and 2. A restraint current of 2 (16, 16 ') is calculated (S6).

Subsequently, as shown in FIGS. 7A and 7B, the microprocessor 12 includes the steady current of the motors 1 and 2 (16 and 16 ′) calculated in step S5 and the motors 1 and 2 calculated in step S6. A predetermined range between the restraint currents of 2 (16, 16 ') is set to the overcurrent detection reference currents 1 and 2 of each motor for judging the overcurrent state (S7).

That is, it calculates the individual steady current and the individual restraint current of each motor for each drive input condition according to the dual motor used in the whole driving area of the dual motor, and the predetermined range between the calculated normal current and the restraint current, for example, the steady current By setting the intermediate value between and the restraint current as the overcurrent detection reference current, the overcurrent detection reference current can be changed for the driving input conditions of all the dual motors, so that the overcurrent state of the dual motor can be detected more accurately.

Thereafter, the microprocessor 12 compares the detection currents 1 and 2 of the motors 1 and 2 (16 and 16 ') measured in the step S4 with the overcurrent detection reference currents 1 and 2 set in the step S7, respectively. That is, the detection current 1 of the motor 1 16 and the overcurrent detection reference current 1 are first compared (S8). If the detection current 1 is larger than the reference current 1, the motor 1 16 is determined to be in the overcurrent state for a predetermined time. (15 seconds), the motors 1 and 2 (16, 16 ') are all stopped driving (S9, S10). If the detection current 1 is less than the reference current 1, it is determined that the motor 1 (16) is in a normal state. Next, the detection current 2 of the motor 2 16 ′ is compared with the overcurrent detection reference current 2 (S11).

As a result of the comparison of the step S11, if the detection current 2 of the motor 2 16 'is less than the overcurrent detection reference current 2, the motor 2 16' is also determined to be in a normal state and the motor 1, 2 (16, 16 ') If the detection current 2 of the motor 2 16 'is greater than the overcurrent detection reference current 2, the motor 2, 16' is determined to be in the overcurrent state for the motor 2 16 '. 16 ') All stop driving (S9, S10).

As described above, in the present invention, since the individual steady current and the individual restraint current of the dual motor exist with respect to the driving input conditions of all the motors, when the overcurrent condition occurs in one motor or both motors when the dual motor is driven, By detecting, burnout of the dual motor due to overcurrent is prevented, and the dual motor can be driven in a stable state.

As described above, according to the present invention, in detecting an overcurrent state of an automotive DC dual motor, the overcurrent may have a predetermined range between the steady current and the restraint current of each motor for each driving input condition according to each used motor. It is set to the detection reference current and detects the current of each motor flowing through the FET through the shunt resistor and the differential amplifier circuit and compares it with the set overcurrent detection reference current. The more accurate detection of the overcurrent condition for the motors has the effect of being able to prevent the burnout of each motor in advance.

That is, it calculates the individual steady current and the individual restraint current of each motor for each drive input condition according to the dual motor used in the whole driving area of the dual motor, and the predetermined range between the calculated normal current and the restraint current, for example, the steady current By setting the intermediate value between and the restraint current as the overcurrent detection reference current, the overcurrent detection reference current can be changed for the driving input conditions of all the dual motors, so that the overcurrent condition occurs in one or both motors when the dual motor is driven. In this case, it is possible to accurately detect this to prevent the burnout of the dual motor due to the overcurrent, and to drive the dual motor in a more stable state.

Claims (4)

An input unit for converting and inputting an external square wave signal including motor driving information (duty) into a potential recognizable by a microprocessor to be described later; Outputs a FET driving control signal for driving the FET according to the motor driving information in the external square wave signal of the input unit, and the steady current and the restraining current of each motor for each driving input condition according to each used motor in the entire driving region of the dual motor. Set a predetermined range between each of the overcurrent detection reference currents 1 and 2 for determining the overcurrent state, and the motor detection currents 1 and 2 corresponding to the output voltages of the smoothing units 1 and 2 to be described later and the set reference currents 1 and 2, respectively. Comparing 2, if the detection current 1 is less than the reference current 1, it is determined as the normal state for the motor 1, if the detection current 2 is less than the reference current 2, it is determined as the normal state for the motor 2 If it is large, the microprocessor for controlling to stop the operation of the motor 1 and the motor 2 when one of the two motors is determined to be in the overcurrent state is determined as the over-current state, A FET driving unit 1 for amplifying and outputting a FET driving signal for driving the motor 1 according to the FET driving control signal of the microprocessor; A FET driver 2 connected to one end of the FET driver 1 to amplify and output the FET drive signal for driving the motor 2 according to the FET drive control signal of the microprocessor output to the FET driver 1; FETs 1 and 2 which are turned on / off according to the FET driving signals of the FET drivers 1 and 2; Freewheeling diodes 1 and 2 which pass regenerative current for continuous operation of each motor 1 and 2 when the FETs 1 and 2 are turned off; Motors 1 and 2 which are driven according to the operations of the FETs 1 and 2 and the freewheeling diodes 1 and 2 to provide a driving force necessary for driving an automobile; Shunt resistors 1 and 2 connected to one end of the FETs 1 and 2 for detecting currents of the motors 1 and 2 flowing through the respective FETs 1 and 2; Amplifier for detecting and amplifying the voltage generated by the current flowing through each of the shunt resistors 1 and 2 while eliminating the effect of the ground potential that changes according to the current for each motor capacity generated when driving a dual motor using a differential amplifier. With 2, The over-current detection device of a dual motor for a vehicle, characterized in that it comprises a smoothing unit 1, 2 for smoothing each voltage amplified by the amplifying unit 1, 2 to output to the microprocessor. The method of claim 1, The FET driver 2 is configured to receive a FET drive control signal for driving the motor 2 directly from the microprocessor, so that the drive control for each motor is individually according to the detection result of the over-current state for each motor during the dual motor drive Overcurrent detection device of a dual motor for cars, characterized in that consisting of. The method of claim 1,  The microprocessor measures the voltage and temperature applied to the motors 1 and 2, and calculates the steady current and the restraint current of the motors 1 and 2 by adding and correcting the changes according to the measured motor applied voltage and temperature. An overcurrent detection device for a dual motor for a vehicle. The method according to claim 1 or 3, And the overcurrent detection reference currents 1 and 2 are set to intermediate values between the steady state and restraint currents of the motors 1 and 2 calculated by the microprocessor.

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